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排序方式: 共有143条查询结果,搜索用时 15 毫秒
1.
We describe CHAMP (CHurn Analysis, Modeling, andPrediction), an automated system for modeling cellularsubscriber churn that is predicting which customerswill discontinue cellular phone service. We describevarious issues related to developing and deployingthis system including automating data access from aremote data warehouse, preprocessing, featureselection, model validation, and optimization toreflect business tradeoffs. Using data from GTE'sdata warehouse for cellular phone customers, CHAMP iscapable of developing churn models customized byregion for over one hundred GTE cellular phone marketstotaling over 5 million customers. Every month churnfactors are identified for each geographic region andmodels are updated to generate churn scores predictingwho is likely to churn in the short term. Learningmethods such as decision trees and genetic algorithmsare used for feature selection and a cascade neuralnetwork is used for predicting churn scores. Inaddition to producing churn scores, CHAMP alsoproduces qualitative results in the form of rules andcomparison of market trends that are disseminatedthrough a web based interface. 相似文献
2.
A chemical mechanical polishing model incorporating both the chemical and mechanical effects 总被引:3,自引:0,他引:3
A comprehensive model for the material removal in a chemical mechanical polishing (CMP) process is presented in which both chemical and mechanical effects are taken into consideration. The chemical effects come into play through the formation of chemically modified surface layer on the wafer surface that, in turn, is removed mechanically by the plastic deformation induced by slurry particles. This model describes the influence of most, if not all, variables involved in the CMP process including slurry characteristics (solid loading, particle size and distribution, modulus), pad properties (modulus, hardness, asperity sizes and distribution) and processing conditions (down-pressure, velocity). Although more elaborate experimental verification of the model is yet to follow, this model appears to be capable of explaining many experimental observations on both oxide and metal CMP that, otherwise, could not be explained properly. 相似文献
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Salleh Emee Marina Zuhailawati Hussain Ramakrishnan Sivakumar Dhindaw Brij Kumar 《Metallurgical and Materials Transactions A》2017,48(5):2519-2528
Metallurgical and Materials Transactions A - Magnesium (Mg) and its alloys have shown potential for use in the biomedical industry due to their excellent biological performance and biodegradability... 相似文献
6.
S. Tzamtzis N.S. Barekar N. Hari Babu J. Patel B.K. Dhindaw Z. Fan 《Composites Part A》2009,40(2):144-151
Particulate metal matrix composites (PMMCs) have attracted interest for application in numerous fields. The current processing methods often produce agglomerated particles in the ductile matrix and as a result these composites exhibit extremely low ductility. The key idea to solve the current problem is to adopt a novel Rheo-process allowing the application of sufficient shear stress (τ) on particulate clusters embedded in liquid metal to overcome the average cohesive force or the tensile strength of the cluster. In this study, cast A356/SiCp composites were produced using a conventional stir casting technique and a novel Rheo-process. The microstructure and properties were evaluated. The adopted Rheo-process significantly improved the distribution of the reinforcement in the matrix. A good combination of improved ultimate tensile strength (UTS) and tensile elongation (ε) is obtained. 相似文献
7.
Frank R. Juretzko Doru M. Stefanescu Brij K. Dhindaw Subhayu Sen Peter A. Curreri 《Metallurgical and Materials Transactions A》1998,29(6):1691-1696
Directional solidification experiments have been carried out to determine the pushing/engulfment transition for two different
metal/particle systems. The systems chosen were aluminum/zirconia particles and zinc/zirconia particles. Pure metals (99.999
pct A1 and 99.95 pct Zn) and spherical particles (500 μm in diameter) were used. The particles were nonreactive with the matrices within the temperature range of interest. The experiments
were conducted so as to ensure a planar solid/liquid (SL) interface during solidification. Particle location before and after
processing was evaluated by X-ray transmission microscopy (XTM) for the Al/ZrO2 samples. All samples were characterized by optical metallography after processing. A clear methodology for the experiment
evaluation was developed to unambiguously interpret the occurrence of the pushing/engulfment transition (PET). It was found
that the critical velocity for engulfment ranges from 1.9 to 2.4 μm/s for Al/ZrO2 and from 1.9 to 2.9 μm/s for Zn/ZrO2. 相似文献
8.
Web Mining 总被引:1,自引:0,他引:1
9.
This paper aims to provide a sketch of the ways in which ‘formal’ institutions of democratic representation worked in practice
in Durban/eThekwini in the 2000-2004 period. In so doing, it assesses how the representation of eThekwini’s citizens functioned
at both the ward and metropolitan levels. After outlining the formation of the new metropolitan political arena, we consider
the relationships amongst political parties at Metro and Ward levels, and, in particular, explore some contextually specific
forms of democratic practice which emerged through the interaction of proportional representation and ward representation
over time. The election of councillors as such does not resolve a series of dilemmas concerning how to institutionalise democratic
representation within a racially diverse, spatially divided, and rapidly changing metropolitan area. Electoral-representative
aspects of a urban democratisation are not a straightforward ‘formal’ framework alongside which other processes of democratic
discussion, mobilisation and contestation can be easily situated.
相似文献
Brij MaharajEmail: |
10.
Nusselt number and friction factor correlations for solar air heater duct having artificially roughened absorber plate 总被引:1,自引:0,他引:1
An experimental investigation has been carried out for a range of system and operating parameters in order to analyse effect of artificial roughness on heat transfer and friction in solar air heater duct having protrusions as roughness geometry. An increase in heat transfer and friction loss has been observed for duct having roughened absorber plate. Experimental data have been used to develop Nusselt number and friction factor correlations as function of system and operating parameters for predicting performance of the system having investigated type of roughness geometry. 相似文献